Jimmy Hill became a hero to Coventry fans after leading them to top flight in 1967. Photograph: Aubrey Hart/Getty Images

Ron Atkinson used to say if the Titanic had been painted sky blue it would not have gone down. For Coventry City, though, the time to scramble for lifejackets and sound the SOS alarm may soon be nigh. Without a manager and yet to win a league game this season going into Sunday's encounter with Stevenage, their return to the third tier for the first time since 1964 has deepened the choppy waters that are beginning to threaten the club's very existence.

City's hedge fund owners, Sisu, have long considered pulling their backing and another campaign in League One would only serve to tip Coventry closer to the precipice. If they do not achieve promotion this term, there are real fears of administration or even liquidation. Sisu, who bought Coventry in 2008 when the club were in dire straits, appointed the chief executive, Tim Fisher, last December to try to salvage the £30m lost in four years.

"There is a frustration and that manifested itself with the departure of the manager," he said, following Andy Thorn's recent sacking. "I don't want to play the blame game, we made a strategic business decision to change the man at the helm."

City have received more than 50 applications for the vacant manager's position after they terminated Thorn's contract. The former Wimbledon defender who enjoyed success with the Crazy Gang spent 16 months in charge after taking the reins on a caretaker basis in March 2011, but started the league campaign with three draws.

For the supporters, it is the lack of clarity from Sisu that remains a key issue. The Mayfair-based owners rarely, if ever, attend games and are trying to buy a 50% stake in the stadium, currently owned equally by Coventry city council and the Higgs Trust, which has been the club's home since an ill-fated switch from Highfield Road in 2005.

While matters off the pitch are perhaps the most pressing concern, the turbulence that has engulfed City has not surprisingly been mirrored on it. Relegation from the Premier League in 2001 ended 34 years in the top flight, before 11 seasons in the Championship were brought to a bitter denouement. This summer has seen the departure of experienced players such as Richard Keogh, Sammy Clingan and Martin Cranie in a reshape of a squad which still harbours hope of an immediate return to the second tier. Fisher said: "It's a critical season and a critical point for many reasons. At the outset we talked about promotion, that's why the previous incumbent put together the squad that he felt was more than capable of getting a top-six position. There's no reason to believe that in the main that squad doesn't have the talent. We've seen it in flashes, there have been moments of quality. We now need to build on that and get to a consistent level of performance."

On the financial constraints hindering City's progress, he added: "There's been an awful lot of hard work transforming what is a Championship-budgeted club into a League One-budgeted club, because the revenue just falls off a cliff."

The supporters have been vociferous in their attempts to oust Sisu from the club. Chants during games may fall on deaf ears but the Sky Blue Trust has been reinvigorated after a dormant few years. The trust says Coventry's plight is so serious that it has already made contingency plans if D-Day arrives, a potential fan-backed takeover having been discussed as hopes of promotion begin to dwindle even at this early stage.

"What frustrates is they [Sisu] can suddenly find £10m to try and buy the stadium, but they can't pay the rent on it and they can't buy players," said their spokesman, Jan Mokrzycki. "It's obvious they don't give a monkeys about the club. No one else is going to come in and save us, it's up to the fans to do it ourselves. We might as well get in a position to do it now, rather than be like Portsmouth, scrambling around at the last minute trying to get something done.

"Getting rid of the manager after three games – why let the guy bring in nine or 10 journeymen players and then get rid of him? Why didn't they get rid of him at the end of last season and give someone else more of a fighting chance? Now we're wasting time, two or three weeks in limbo. The team in the last two or three games has looked totally unmotivated. When we came down from the Premiership to the Championship, we were in a cosy mid-table position and then dropped from there, I think we're in danger of the same thing happening."

Whoever City appoint as manager in the coming weeks needs the backing of everyone at the club. Fisher remains confident of a revival: "We're turning the ship and we're turning the ship in choppy waters." Coventry must hope there will be calm after the storm.

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